Of the four million faulty airbag inflators auto parts maker Takata Corp. is beginning to replace in U.S. vehicles, confusion remains as to the total number of vehicles that still may possess defective parts. Safety regulators contend that 400,000 of the previously-replaced airbag inflator components will need to be re-done, as these vehicles were repaired using a potentially defective propellant. However, the efficacy of more than three million of the inflators remain unknown as Takata is not able to confirm just how many vehicles remain on the road with defective parts and whether driver-side, passenger-side, or both airbags are affected. Furthermore, since Takata’s May 2015 disclosure to NHTSA that up to 34 million vehicles were installed with the defective inflators, eight of ten automakers that use Takata airbags have issued wider recalls. Prone to spewing metal shrapnel into vehicles upon spontaneous explosion, the faulty inflators have been blamed for at least 6 deaths and hundreds of injuries.